21000110123 has 2 divisors, whose sum is σ = 21000110124. Its totient is φ = 21000110122.

The previous prime is 21000110057. The next prime is 21000110137. The reversal of 21000110123 is 32101100012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21000110123 - 2¹⁰ = 21000109099 is a prime.

It is not a weakly prime, because it can be changed into another prime (21000110143) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500055061 + 10500055062.

It is an arithmetic number, because the mean of its divisors is an integer number (10500055062).

Almost surely, 2^21000110123 is an apocalyptic number.

21000110123 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000110123 is an equidigital number, since it uses as much as digits as its factorization.

21000110123 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12, while the sum is 11.

Adding to 21000110123 its reverse (32101100012), we get a palindrome (53101210135).

The spelling of 21000110123 in words is "twenty-one billion, one hundred ten thousand, one hundred twenty-three".